H. Wösten

Wageningen University & Research | WUR · Soil Sciences

Soils and their properties play an important role in land evaluation studies. Often such studies focus on larger scales ranging from watersheds up to the national scale or even larger. Soil properties are often known at smaller scales, sometimes at the level of individual soil samples. The aim of this study is to show how point information on soil...

The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world ("International Peat Congress with over 1000 participants!," 2016). The congress covered all aspects of peatland ecosystems and their management, with a...

The change in the Common Agricultural Policy (CAP) of the European Union from product to producer support, including requirements for ‘good agricultural and environmental conditions’ and ‘greening’, is excellent. However, these requirements are now defined in rather general terms. Questions can be raised about suitable indicators, and there is a re...

There is a common need for reliable hydropedological information in Europe. In the last decades research institutes, universities and government agencies have developed local, regional and national datasets containing soil physical, chemical, hydrological and taxonomic information often combined with land use and landform data. A hydrological datab...

Water retention and hydraulic conductivity characteristics of the soil are indispensable for hydrological catchment modelling and for quantifying water limited agricultural production. However, these characteristics are often not available for regions and data scarcity for tropical zones is even bigger than for temperate zones. Use of pedotransfer...

Forested tropical peatlands in Southeast Asia store at least 42 000 Million metric tonnes (Mt) of soil carbon. Human activity and climate change threatens the stability of this large pool, which has been decreasing rapidly over the last few decades owing to deforestation, drainage and fire. In this paper we estimate the carbon dioxide (CO<sub>2</su...

Extensive degradation of Indonesian peatlands by deforestation, drainage and recurrent fires causes release of huge amounts of peat soil carbon to the atmosphere. Construction of drainage canals is associated with conversion to other land uses, especially plantations of oil palm and pulpwood trees, and with widespread illegal logging to facilitate...

Delta Session DS 9: The lowland deltas of Indonesia. Hydrological restoration of Indonesian peatlands to mitigate carbon dioxide emissions, Henk Wösten (2010). Presented at the international conference Deltas in Times of Climate Change, 29 September - 1 October, Rotterdam, the Netherlands.

Forested tropical peatlands in Southeast Asia store at least 42 000 Million metric tonnes (Mt) of soil carbon. Human activity and climate change threatens the stability of this large pool, which has been decreasing rapidly over the last few decades owing to deforestation, drainage and fire. In this paper we estimate the carbon dioxide (CO2) emissio...

Studies of restoration ecology are well established for northern peatlands, but at an early stage for tropical peatlands. Extensive peatland areas in Southeast Asia have been degraded through deforestation, drainage and fire, leading to on- and off-site environmental and socio-economic impacts of local to global significance. To address these probl...

Large areas of globally important tropical peatland in Southeast Asia are under threat from land clearance, degradation and fire, jeopardizing their natural functions as reservoirs of biodiversity, carbon stores and hydrological buffers. If the initially waterlogged peat swamps are drained to grow agricultural or plantation crops this leads unavoid...

CO2 emissions from drained peat lands form a significant part of global carbon emissions and have become an important part of the global debate on climate change. Mitigation of land use based carbon emissions can only be achieved by internalizing the issue in spatial planning. In this paper we summarize the efforts made so far with respect to peat...

Interrelationships between peat and water were studied using a hydropedological modelling approach for adjacent relatively intact and degraded peatland in Central Kalimantan, Indonesia. The easy to observe degree of peat humification provided good guidance for the assignment of more difficult to measure saturated hydraulic conductivities to the acr...

A biophysically-oriented study on land suitability for oil palm in Kalimantan, Indonesia was done. It provides a sound, biophysically oriented basis for the allocation of new oil palm plantations or intensification of existing palm oil plantations, focusing on Kalimantan but other areas could be taken into account in the future. Our study shows th...

Human induced land use change and associated fire alter profoundly the hydrology of tropical peatlands and thus affect the functioning of entire river catchments. The hydrological model SIMGRO was used to calculate the effects of drainage on peat water levels, peat surface morphology and river flows within the Air Hitam Laut catchment in Jambi Prov...

About one quarter of the world’s tropical peatlands (11 million hectares) occur in Borneo. These peatlands have global ecological signi fi cance, being some of the largest remaining areas of lowland rainforest in South East Asia that provide the habitat of many endangered species. In addition, they are large stores of carbon and water and have an i...

Solute leaching in unsaturated soil is influenced by the variability in hydraulic functions (water retention and conductivity) that govern the flow process. Variability in measured soil hydraulic functions of a coarse-, medium- and fine-textured soil group was quantified with the scaling theory of similar media. Solute leaching in these soils was c...

Computer simulation of the soil water regime was used to calculate moisture deficits for Pleistocene and fluvial Holocene clay soils for a 30-year period. Hydraulic conductivity (K-h) and moisture retention (h-θ) data were derived for major horizons in both soils as well as functions to characterize bypass flow and effects of horizontal planar void...

Pedotransfer functions (PTFs) have become a topic drawing increasing interest within the field of soil and environmental research because they can provide important soil physical data at relatively low cost. Few studies, however, explore which contributions PTFs can make to land-use planning, in terms of examining the expected outcome of certain ch...

Interrelationships between hydrology and ecology are established for the Air Hitam Laut watershed in Jambi Province, Sumatra, Indonesia. The developed relational diagram shows how modelled regional groundwater levels and flooding patterns are related to the occurrence of different vegetation types in this endangered peatland watershed. In dry condi...

Human induced land use change and associated fires change profoundly the hydrology of tropical peatlands and thus affect the functioning of entire river basins. An hydrological model was used to calculate the effects of drainage on groundwater levels, peat surface morphology and river flows for the Air Hitam Laut watershed in Jambi Province, Sumatr...

This chapter presents procedures that can be used for pedotransfer functions (PTFs) evaluation. Model testing requires that both model inputs and measured data vs. model estimates must be carefully assessed to avoid a blind evaluation that would produce unreliable results. Preliminary data quality evaluation is the key to provide the basis for mode...

Soil maps of Europe, published by the EU and the European Soil Bureau Network; with varying scales 1:1.500.000 1:1.750.000 1:2.000.000 1:2.200.000 1:2.500.000 1:3.000.000 1:6.500.000

For the development of pedotransfer functions (PTFs), large and good quality data sets comprising measured hydraulic characteristics of a wide variety of soils are required. An example of such a large data set is the database of hydraulic properties of European soils (HYPRES). In a study discussed in the chapter, PTFs for the different texture clas...

The United Nations Framework Convention on Climate Change (UNFCCC) has opened the way, via the Kyoto Protocol, to seek globally the most cost effective way to reduce carbon emissions or enhance terrestrial carbon sinks. Industrialised countries may thus achieve part of their emission reduction target by afforestation and reforestation projects in t...

The objective of this paper is to contribute to the ongoing discussion on strengths, weaknesses, opportunities and trends of existing modeling approaches in soil hydrology. We present a comprehensive case study of using integrated data to build a model of groundwater pollution for a watershed, and use this case study to illustrate current opportuni...

Large areas of globally important tropical peatland in Southeast Asia are threatened by land clearance, degradation and fire, jeopardising their natural functions as reservoirs of biodiversity, carbon stores and hydrological buffers. Many development projects on tropical peatlands have failed because of lack of understanding of the landscape functi...

Estimation of soil hydraulic properties by pedotransfer functions (PTFs) can be an alternative to troublesome and expensive measurements. New approaches to develop PTFs are continuously being introduced, however, PTF applicability in locations other than those of data collection has been rarely reported. We used three databases were used to develop...

In this paper aspects of fire , forest ecosystems and peat bogs are discussed with special reference to peat forest bogs in SE Asia and fire prevention options.

Water retention and hydraulic conductivity are crucial input parameters in any modelling study on water flow and solute transport in soils. Due to inherent temporal and spatial variability in these hydraulic characteristics, large numbers of samples are required to properly characterise areas of land. Hydraulic characteristics can be obtained from...

Quantifying water flow and chemical transport in the vadose zone typically requires knowledge of the unsaturated soil hydraulic properties. The UNsaturated SOil hydraulic DAtabase (UNSODA) was developed to provide a source of unsaturated hydraulic data and some other soil properties for practitioners and researchers. The current database contains m...

Of the global land area, about 38% is agricultural land of which some 30% is arable land (faostat.fao.org). The relations between agriculture and the natural environment are complex. Agriculture is of vital importance to many societies and is the sector with the most intensive interaction between man and environment. Agriculture has, by its very na...

The government of Sarawak has identified the populated coastal zone of Sarawak as a major region for agricultural development, which will be partly on peat. At the same time the government recognizes that the characteristic flora and fauna give the peat swamps in this zone the status of unique ecosystems, which are internationally recognised as val...

Het bij Alterra aanwezige bestand van gemeten bodemfysische karakteristieken is de laatste jaren aanzienlijk uitgebreid. Deze uitbreiding heeft geleid tot een vernieuwing van de in 1994 uitgebrachte Staringreeks. De Staringreeks vermeldt de gemiddeldebodemfysische karakteristieken voor alle onderscheiden 18 boven- en 18 ondergronden. De reeks geeft...

Many environmental and agricultural problems are not restricted to national boundaries and therefore require international cooperation if solutions are to be found. Often, these solutions require the ability to use soil data as input in simulation models, however, despite a number of recognised international standards, soil data are rarely compatib...

Many environmental studies on the protection of European soil and water resources make use of soil water simulation models. A major obstacle to the wider application of these models is the lack of easily accessible and representative soil hydraulic properties. In order to overcome this apparent lack of data, a project was initiated to bring togethe...

One way of addressing the paucity of soil hydraulic data for simulation modeling is through the use of pedotransfer functions. In this case soils data routinely collected during systematic soil surveys are used to predict the soil hydraulic characteristics. To derive pedotransfer functions for European soils 18 institutions in 10 EU countries parti...

This workshop was the second of a project on using existing soil data to derive hydraulic parameters for simulation modelling in environmental studies and in land use planning, funded by the European Union. Section 1 of the proceedings highlights workdone by the network partners on the topic of pedotransfer. Section 2 describes the HYPRES database...

Both hysteresis and preferential flow affect soil water movement in the unsaturated zone. The agrohydrological numerical model in which these two processes have been included was applied to data sets from two sites with hysteretic and water-repellent soils. It was found that hysteresis retards soil water movement, whereas preferential flow enhances...

Uncertainties in major input variables in water and solute models were quantified and their effects on simulated functional aspects of soil behaviour were studied using basic soil properties from an important soil mapping unit in the Netherlands. The major sources of uncertainty were: (i) spatial variability of basic soil properties such as soil pr...

Soil maps are used to characterize spatial patterns of soil behaviour. A first approach is to characterize each soil map unit (SMU) by the behaviour of a pedogenetically representative profile; a second is to subsample each SMU and select from the sample a characteristic profile by its behaviour. The first approach was tested against the second. Us...

Scientists have developed complex computer models to simulate water and solute movement in the unsaturated and saturated zones. Lack of relevant input data is considered a major obstacle to progress. Therefore, existing databases have been used to derive input data from measured soil data. Pedotransfer functions (PTFs) have been selected for predic...

Class pedotransfer functions (PTF) and continuous PTFs were used to generate soil hydraulic characteristics. Both approaches were used to predict the soil physical input data to calculate five functional aspects of soil behaviour: number of workable days, number of days with adequate soil aeration, elapsed time until 10% breakthrough of chloride, a...

The data crisis in scenario studies embodies topics such as (i) the relevance of existing data for current and forthcoming models; (ii) deciding on the use ofexisting soil data or sampling new data ; (iii) the sensivity of models to several sources of uncertainty in model inputs and consequences for data sampling; (iv) pragmatic approaches to the d...

The data crisis in scenario studies embodies topics such as: the relevance of existing data to models; decisions between using existing soil data or sampling new data; the sensitivity of models to several sources of uncertainty in model inputs and consequences for data sampling; pragmatic approaches to the data crisis; and the presentation of uncer...

Measurements of soil hydraulic conductivity and water retention functions that are needed to run soil water balance and/or crop growth simulation models are expensive and time consuming. The number of such measurements can be reduced considerably if “classical” soil horizons that are to be sampled can be merged into broader, hydraulic functional ho...

A technique is presented to measure in-situ infiltration rate and pressure head gradients within a puddled rice soil. Measurements at 33 sites within a small 0.1 ha plot indicated unsaturated flow conditions in the non-puddled subsoil. The least permeable layer within the profile, as determined by the greatest gradient in pressure head, was found t...

Systems approaches for agricultural development can be realized at different levels of detail which are associated with different data needs. For soils five levels were defined, ranging from farmer’s knowledge and expert systems to use of complex simulation models. Any problem to be studied should be analyzed thoroughly beforehand and the most appr...

Soil hydraulic functions can be obtained with methods that range from complex and costly to simple and cheap. Decisions as to which is the most appropriate method for a specific application have to be based on a comparison of generated hydraulic functions. This comparison should preferably be based on a statistical comparison of practical applicati...

In this study, four different methods were used to generate soil hydraulic functions: Method A, direct on-site measurement; Method B, use of measured hydraulic functions averaged on a regional scale; Method C, use of measured hydraulic functions averaged on a national scale; and Method D, use of van Genuchten parameters correlated with soil texture...

Saturated and unsaturated hydraulic-conductivity and moisture-retention data were measured in 25 C horizons with a sand texture and in 23 C horizons with a clay loam and silty cl